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•The effects of polyester fibers on soil animals were studied for the first time.•Enchytraeid reproduction decreased up to 30% but only by long fibers in soil.•Isopod energy reserves ...and feeding activity were affected by fibers in soil.•Polyester fibers were not very harmful to soil invertebrates in 21–28-days exposure.•Polyester fibers can enter terrestrial food webs by ingestion by soil invertebrates.
Polyester fiber is one of the most abundant types of microplastics in the environment. A major proportion of the fibers entering wastewater treatment plants end up in sewage sludge, which is used as a soil fertilizer in many countries. As their impacts in the terrestrial environment are still poorly understood, we studied the effects of polyester fibers on enchytraeids (Enchytraeus crypticus), springtails (Folsomia candida), isopods (Porcellio scaber) and oribatid mites (Oppia nitens), all playing an important role in soil decomposer food webs. We exposed these invertebrates in the laboratory to short (12 µm–2.87 mm) and long (4–24 mm) polyester fibers, spiked in soil or in food at five concentrations ranging from 0.02% to 1.5% (w/w) and using five replicates. Overall the effects of polyester fibers on the soil invertebrates were slight. Energy reserves of the isopods were slightly affected by both fiber types, and enchytraeid reproduction decreased up to 30% with increasing fiber concentration, but only for long fibers in soil. The low ingestion of long fibers by the enchytraeids suggests that this negative impact arose from a physical harm outside the organism, or from indirect effects resulting from changes in environmental conditions. The short fibers were clearly ingested by enchytraeids and isopods, with the rate of ingestion positively related to fiber concentration in the soil. This study shows that polyester fibers are not very harmful to soil invertebrates upon short-term exposure. However, longer lasting, multigeneration studies with functional endpoints are needed to reveal the possible long-term effects on soil invertebrates and their role in the decomposition process. This study also shows that polyester fibers can enter terrestrial food web via ingestion of fibers by soil invertebrates.
The impact of microplastic pollution on terrestrial biota is an emerging research area, and this is particularly so for soil biota. In this study, we addressed this knowledge gap by examining the ...impact of aged low-density polyethylene (LDPE) and polyester fibres (i.e. polyethylene terephthalate, PET) on a forest microbiome composition and activity. We also measured the corresponding physicochemical changes in the soil. We observed that bacteria community composition diverged in PET and LDPE treated soils from that of the control by day 42. These changes occurred at 0.2% and 0.4% (w/w) of PET and at 3% LDPE. Additionally, soil respiration was 8-fold higher in soil that received 3% LDPE compared to other treatments and control. There were no clear patterns linking these biological changes to physicochemical changes measured. Taken together, we concluded that microplastics aging in the environment may have evolutionary consequences for forest soil microbiome and there is immediate implication for climate change if the observed increase in soil respiration is reproducible in multiple ecosystems.
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•We investigate the response of forest soil bacteria community to microplastics.•Soil respiration increased 8-fold with 3% low-density polyethylene (LDPE).•Soil microbiome diverged in polyester fibre (PET) and LDPE treated soils.•Evolutionary and climate change effects of microplastics need further research.
Microplastics and agrochemicals are common pollutants in terrestrial ecosystems. Their interaction during coexistence in soils may influence their fate and adverse effects on terrestrial organisms. ...The aim of this study was to investigate how the exposure to two types of microplastics; polyester fibres, and crumb rubber; induce changes in immune parameters of Porcellio scaber and if the co-exposure of microplastics affects the response induced by the organophosphate pesticide chlorpyrifos. A number of immune parameters, such as total haemocyte count, differential haemocyte count, and phenoloxidase-like activity were assessed. In addition, the acetylcholinesterase (AChE) activity in the haemolymph was evaluated as a measure of the bioavailability of chlorpyrifos. After three weeks of exposure, the most noticeable changes in the measured immune parameters and also a significantly reduced AChE activity were seen in chlorpyrifos-exposed animals. Both types of microplastic at environmentally relevant concentrations caused only slight changes in immune parameters which were not dependent on the type of microplastic, although the two types differed significantly in terms of the chemical complexity of the additives. Mixtures of chlorpyrifos and microplastics induced changes that differed from individual exposures. For example, alterations in some measured parameters suggested a reduced bioavailability of chlorpyrifos (AChE activity, haemocyte viability) caused by both types of microplastics exposure, but the increase of haemocyte count was promoted by the presence of fibres implying their joint action. In conclusion, this study suggests that immune processes in P. scaber are slightly changed upon exposure to both types of microplastics and microplastics can significantly modulate the effects of other co-exposed chemicals. Further research is needed on the short-term and long-term joint effects of microplastics and agrochemicals on the immunity of soil invertebrates.
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•Immune parameters are slightly changed upon exposure to plastic fibres or crumb rubber.•Chlorpyrifos caused significant changes in Porcellio scaber immune parameters.•Microplastics decreased the bioavailability of chlorpyrifos for P. scaber.•Mixtures of plastic fibres and chlorpyrifos resulted in greater response in haemocyte count.
Microplastics are very common contaminants in the environment. Despite increasing efforts to assess the effects of microplastics on soil organisms, there remains a lack of knowledge on how organisms ...respond to diverse types of microplastics after different exposure durations. In the present study, we investigated the immune response of the terrestrial crustacean Porcellio scaber exposed to the two most common microplastic particles in the environment: polyester fibres and tyre particles. We also tested two natural particles: wood dust and silica powder, with all treatments performed at 1.5% w/w. The response of P. scaber was evaluated at the level of the immune system, and also the biochemical, organism and population level, after different exposure durations (1, 2, 4, 7, 14, 21 days). These data reveal dynamic changes in the levels of some immune parameters shortly after exposure, with a gradual return to control values. The total number of haemocytes was significantly decreased after 4 days of exposure to tyre particles, while the proportion of different haemocyte types in the haemolymph was altered shortly after exposure to both polyester fibres and tyre particles. Moreover, 7 days of exposure to tyre particles resulted in increased superoxide dismutase activity in the haemolymph, while metabolic activity in whole woodlice (measured as electron transport system activity) was increased after exposure for 7, 14 and 21 days. In contrast, the natural particles did not elicit any significant changes in the measured parameters. Survival and feeding of P. scaber were not altered by exposure to the microplastics and natural particles in soil. Overall, this study defines a time-dependent transient immune response of P. scaber, which indicates that immune parameters represent sensitive biomarkers of exposure to microplastics. We discuss the importance of using natural particles in studies of microplastics exposure and their effects.
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•We studied natural particles and microplastics for immune effects in Porcellio scaber•Haemocyte proportions in haemolymph rapidly and transiently changed for microplastics•Exposure to tyre particles significantly increased whole woodlouse metabolic activity•There were no changes in measured parameters for exposure to natural particles
Some types of textile fibres are considered to be the cause of allergic reactions and other adverse health effects on humans. The main compounds behind these health problems usually contain azo ...groups in their chemical structure, which are widely employed as azo dyes in the manufacture of textile and clothing products. In this respect, availability of simple analytical procedures for identifying azo groups in textiles is of concern, not only for toxicological studies, but also for clinical and forensic investigations. In this work, conventional Raman spectrometry was assessed as an analytical tool for identification of the azo function in the extracts of fibres obtained after applying a liquid-solvent extraction procedure to the polyester-based textile products. A medium-polarity solvent of ethanol-diethyl ether (1:1 mixture) was shown to be the most effective extraction medium. Two laser lines at 514.5 nm and 785 nm were compared, with the longer wavelength preferred as additional peaks were identified in the Raman spectrum, which had better signal-to-background and signal-to-noise ratios owing to decreased fluorescence in contrast to excitation at 514.5 nm. The method reported is a convenient procedure that can be applied in many instances when rapid screening of fibre dyes is required.
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•The medium-polarity ethanol-diethyl ether (1:1) mixture is a good extractant for azobenzene disperse dyes.•Conventional Raman spectrometry is very adequate for the identification of azo groups in the ethanol-diethyl ether extracts.•The most suitable excitation source for Raman spectrometry is the longer wavelength laser line at 785 nm.
•Performance of RPC with PP and PE fibres at elevated temperatures is evaluated.•Combined effect of PP and PE fibre based RPC, possess good spalling resistance with 0.1% fibre content.•Microstructure ...examination of all RPC mixes is performed, to investigate formation of pores, cracks and evaporation of fibres.
Reactive Powder Concrete (RPC) is an emerging class of special concrete that falls under the category of ultra-high-performance concrete. RPC offers very superior mechanical properties as compared to conventional concretes. The application of RPC is limited to some of the restricted applications such as, construction of nuclear power plants, precast bridges and girders. The generalized application of RPC is restricted due to the unknown behavior of RPC, when it is exposed to fire load. The dense and fine microstructure of RPC is prone to spalling under elevated temperatures. To combat spalling, RPC is produced with suitable fibres. In this study RPC is prepared with addition of polypropelene and polyester fibres with different fibre dosages like 0.1, 0.5 and 0.9% by weight of cement. The residual mechanical and durability properties of fibre-based RPC are evaluated at elevated temperatures ranging from 200 to 800 °C. Results indicate that the combined effect of polypropelene and polyester fibre-based RPC, possess good spalling resistance with 0.1% fibre content. Fibre dosage of 0.5% has shown superior residual mechanical and durability properties of RPC at elevated temperatures. Formation of pores, cracks and evaporation of fibres due to elevated temperatures is also investigated based on microstructure examination for all RPC mixes.
Surface contact electrification experiments have been performed on insulating polyester fibres in contact with a conductive fibre using biased atomic force microscopy tips. With positive tip bias, ...charge spots have been deposited in a reproducible manner. The density of deposited charges on the fibre surface was observed by Kelvin probe force microscopy as a function of time, charging position and relative humidity. Two main charge dissipation mechanisms were identified with different importance depending on the relative humidity value.
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•Novel experimental setup to perform Kelvin probe force microscopy (KPFM) on individual fibres.•Electrical charges deposition on individual polyester fibres.•KPFM surface potential measurements are used to monitor the charge decay processes.•The field-adsorbed water meniscus mechanism is the main process for charging.•The dissipation mechanism depends on the relative humidity.
Approximately 95 million tones of fly is generated in India yearly, and most of the fly ash is of Class F type. Out of which only around 15–20% is utilized in cement production and cement/concrete ...related activities. Since large scale utilization of large volumes of fly ash in various concrete applications is a becoming a more general practice, an investigation was carried out to investigate the compressive strength and abrasion resistance of high volume fly ash concrete (HVFA) concrete with polyester fibres.
In this paper, abrasion resistance of high volume fly ash (HVFA) concretes made with 30%, 40%, and 50% of cement replacement was evaluated in terms of its relation with compressive strength. Comparison was made between ordinary Portland cement and fly ash concrete. Test results indicated that abrasion resistance of concrete having cement replacement up to 30% was comparable to the normal concrete mixture with out fly ash. Beyond 30% cement replacement, fly ash concretes exhibited slightly lower resistance to abrasion relative to non-fly ash concretes. Inclusion of polyester fibres in HVFA concretes improved the abrasion resistance of concrete. Test results further indicated that abrasion resistance of concrete is closely related with compressive strength, and had a very good correlation between abrasion resistance and compressive strength (R2) value between 0.9208 and 0.804 depending upon fly ash content, testing age, and percentage of polyester fibres.
In order to improve the low-temperature cracking resistance and durability of high-modulus asphalt mixture, this article proposes the use of Trinidad Lake Asphalt (TLA) and polyester fibre complex ...methods to obtain high-modulus asphalt mixture, based on indoor accelerated load, low bending temperature, freeze-thaw splitting and APA fatigue test to study the influence of TLA content on permanent deformation resistance performance, water stability, low-temperature crack resistance and fatigue resistance of high-modulus asphalt mixtures. Meanwhile, it reveals the mechanism of the TLA and polyester fibre composite modified on high-modulus asphalt mixture and recommends the best solution of high-modulus asphalt complex is 30% TLA + 3‰ polyester fibre.
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Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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